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Dysphagia Jun 2023Oral stereognosis is the ability to recognize, discriminate and localize a bolus in the oral cavity. Clinical observation indicates deficits in oral stereognosis in...
Oral stereognosis is the ability to recognize, discriminate and localize a bolus in the oral cavity. Clinical observation indicates deficits in oral stereognosis in patients with vascular or neurodegenerative diseases particularly affecting the parietal lobes. However, the precise neural representation of oral stereognosis remains unclear whereas the neural network of manual stereognosis has already been identified. We hypothesize that oral and manual stereognosis share common neuronal substrates whilst also showing somatotopic distribution. Functional magnetic resonance images (fMRI; Siemens Prisma 3 T) from 20 healthy right-handed participants (11 female; mean age 25.7 years) using a cross-modal task of oral and manual spatial object manipulation were acquired. Data were analyzed using FSL software using a block design and standard analytical and statistical procedures. A conjunction analysis targeted the common neuronal substrate for stereognosis. Activations associated with manual and oral stereognosis were found in partially overlapping fronto-parietal networks in a somatotopic fashion, where oral stereognosis is located caudally from manual stereognosis. A significant overlap was seen in the left anterior intraparietal sulcus. Additionally, cerebellar activations were shown particularly for the oral condition. Spatial arrangement of shaped boli in the oral cavity is associated with neuronal activity in fronto-parietal networks and the cerebellum. These findings have significant implications for clinical diagnostics and management of patients with lesions or atrophy in parietal lobule (e.g. Alzheimer's disease, stroke). More studies are required to investigate the clinical effect of damage to these areas, such as loss of oral stereognosis or an impaired oral phase.
Topics: Humans; Female; Adult; Stereognosis; Magnetic Resonance Imaging; Brain Mapping; Parietal Lobe
PubMed: 36087119
DOI: 10.1007/s00455-022-10517-2 -
ELife Mar 2021Coordinating among the demands of the external environment and internal plans requires cognitive control supported by a fronto-parietal control network (FPCN). Evidence...
Coordinating among the demands of the external environment and internal plans requires cognitive control supported by a fronto-parietal control network (FPCN). Evidence suggests that multiple control systems span the FPCN whose operations are poorly understood. Previously (Nee and D'Esposito, 2016; 2017), we detailed frontal dynamics that support control processing, but left open their role in broader cortical function. Here, I show that the FPCN consists of an external/present-oriented to internal/future-oriented cortical gradient extending outwardly from sensory-motor cortices. Areas at the ends of this gradient act in a segregative manner, exciting areas at the same level, but suppressing areas at different levels. By contrast, areas in the middle of the gradient excite areas at all levels, promoting integration of control processing. Individual differences in integrative dynamics predict higher level cognitive ability and amenability to neuromodulation. These data suggest that an intermediary zone within the FPCN underlies integrative processing that supports cognitive control.
Topics: Adult; Brain Mapping; Cognition; Female; Frontal Lobe; Humans; Magnetic Resonance Imaging; Male; Neural Pathways; Parietal Lobe
PubMed: 33650966
DOI: 10.7554/eLife.57244 -
Acta Neurobiologiae Experimentalis 2005Dyslexia is defined as a specific reading disorder despite normal intelligence and conventional teaching. One of the most influential theories attempting to explain... (Review)
Review
Dyslexia is defined as a specific reading disorder despite normal intelligence and conventional teaching. One of the most influential theories attempting to explain problems suffered by dyslexics assumes that dyslexia is caused by deficits of the magnocellular system. This system, generally responsible for processing fast sensory information, projects mostly to the parietal cortex. Consistent with this theory, dyslexics should have problems with tasks which specifically involve parietal cortex. In the article, we review data and show that, indeed, dyslexics have problems with fast attention shifts, show some symptoms of mild unilateral neglect syndrome and have abnormal saccadic and pursuit eye movements. Little is known about visuo-motor coordination and mental rotation, the tasks in which the parietal cortex is thought to play important roles.
Topics: Dyslexia; Humans; Parietal Lobe
PubMed: 15794034
DOI: 10.55782/ane-2005-1542 -
Neurobiology of Learning and Memory Feb 2009The posterior parietal cortex (PPC) of rats has most recently been defined based on patterns of thalamic and cortical connectivity. The anatomical characteristics of... (Review)
Review
The posterior parietal cortex (PPC) of rats has most recently been defined based on patterns of thalamic and cortical connectivity. The anatomical characteristics of this area suggest that it may be homologous to the PPC of primates and contribute to similar functions. This review summarizes evidence for and against a role for the rat PPC in attention and working memory and evaluates how the function of the rat PPC compares to that of primates on these dimensions. Theories of how the rat PPC contributes to behavior are presented, including the notion that PPC may serve as an interface between attention and learning. Finally, several avenues for future research are considered.
Topics: Animals; Attention; Cognition; Conditioning, Psychological; Humans; Learning; Memory, Short-Term; Neural Pathways; Orientation; Parietal Lobe; Perceptual Disorders; Temporal Lobe
PubMed: 18675370
DOI: 10.1016/j.nlm.2008.07.004 -
ENeuro 2017The statistical structure of intrinsic parietal and parieto-frontal connectivity in monkeys was studied through hierarchical cluster analysis. Based on their inputs,...
The statistical structure of intrinsic parietal and parieto-frontal connectivity in monkeys was studied through hierarchical cluster analysis. Based on their inputs, parietal and frontal areas were grouped into different clusters, including a variable number of areas that in most instances occupied contiguous architectonic fields. Connectivity tended to be stronger locally: that is, within areas of the same cluster. Distant frontal and parietal areas were targeted through connections that in most instances were reciprocal and often of different strength. These connections linked parietal and frontal clusters formed by areas sharing basic functional properties. This led to five different medio-laterally oriented pillar domains spanning the entire extent of the parieto-frontal system, in the posterior parietal, anterior parietal, cingulate, frontal, and prefrontal cortex. Different information processing streams could be identified thanks to inter-domain connectivity. These streams encode fast hand reaching and its control, complex visuomotor action spaces, hand grasping, action/intention recognition, oculomotor intention and visual attention, behavioral goals and strategies, and reward and decision value outcome. Most of these streams converge on the cingulate domain, the main hub of the system. All of them are embedded within a larger eye-hand coordination network, from which they can be selectively set in motion by task demands.
Topics: Animals; Cluster Analysis; Cognition; Computer Simulation; Frontal Lobe; Macaca; Models, Neurological; Motor Activity; Neural Pathways; Parietal Lobe
PubMed: 28275714
DOI: 10.1523/ENEURO.0306-16.2017 -
Neurobiology of Learning and Memory Feb 2009The posterior parietal cortex has been traditionally associated with coordinate transformations necessary for interaction with the environment and with visual-spatial... (Review)
Review
The posterior parietal cortex has been traditionally associated with coordinate transformations necessary for interaction with the environment and with visual-spatial attention. More recently, involvement of posterior parietal cortex in other cognitive functions such as working memory and task learning has become evident. Neurophysiological experiments in non-human primates and human imaging studies have revealed neural correlates of memory and learning at the single neuron and at the brain network level. During working memory, posterior parietal neurons continue to discharge and to represent stimuli that are no longer present. This activation resembles the responses of prefrontal neurons, although important differences have been identified in terms of the ability to resist stimulation by distracting stimuli, which is more evident in the prefrontal than the posterior parietal cortex. Posterior parietal neurons also become active during tasks that require the organization of information into larger structured elements and their activity is modulated according to learned context-dependent rules. Neural correlates of learning can be observed in the mean discharge rate and spectral power of neuronal spike trains after training to perform new task sets or rules. These findings demonstrate the importance of posterior parietal cortex in brain networks mediating working memory and learning.
Topics: Action Potentials; Animals; Brain Diseases; Diagnostic Imaging; Humans; Learning; Macaca; Memory, Short-Term; Neural Networks, Computer; Parietal Lobe
PubMed: 19116173
DOI: 10.1016/j.nlm.2008.12.006 -
PloS One 2021Brain-based deception research began only two decades ago and has since included a wide variety of contexts and response modalities for deception paradigms.... (Meta-Analysis)
Meta-Analysis
Brain-based deception research began only two decades ago and has since included a wide variety of contexts and response modalities for deception paradigms. Investigations of this sort serve to better our neuroscientific and legal knowledge of the ways in which individuals deceive others. To this end, we conducted activation likelihood estimation (ALE) and meta-analytic connectivity modelling (MACM) using BrainMap software to examine 45 task-based fMRI brain activation studies on deception. An activation likelihood estimation comparing activations during deceptive versus honest behavior revealed 7 significant peak activation clusters (bilateral insula, left superior frontal gyrus, bilateral supramarginal gyrus, and bilateral medial frontal gyrus). Meta-analytic connectivity modelling revealed an interconnected network amongst the 7 regions comprising both unidirectional and bidirectional connections. Together with subsequent behavioral and paradigm decoding, these findings implicate the supramarginal gyrus as a key component for the sociocognitive process of deception.
Topics: Adult; Brain; Brain Mapping; Deception; Female; Functional Neuroimaging; Humans; Magnetic Resonance Imaging; Male; Models, Neurological; Nerve Net; Parietal Lobe; Prefrontal Cortex
PubMed: 34432808
DOI: 10.1371/journal.pone.0248909 -
Cerebral Cortex (New York, N.Y. : 1991) Dec 2022Decades of research have highlighted the importance of lateral parietal cortex (LPC) across a myriad of cognitive domains. Yet, the underlying function of LPC remains...
Decades of research have highlighted the importance of lateral parietal cortex (LPC) across a myriad of cognitive domains. Yet, the underlying function of LPC remains unclear. Two domains that have emphasized LPC involvement are semantic memory and episodic memory retrieval. From each domain, sophisticated functional models have been proposed, as well as the more domain-general assumption that LPC is engaged by any form of internally directed cognition (episodic/semantic retrieval being examples). Here we used a combination of functional magnetic resonance imaging, functional connectivity, and diffusion tensor imaging white-matter connectivity to show that (i) ventral LPC (angular gyrus [AG]) was positively engaged during episodic retrieval but disengaged during semantic memory retrieval and (ii) activity negatively varied with task difficulty in the semantic task whereas episodic activation was independent of difficulty. In contrast, dorsal LPC (intraparietal sulcus) showed domain general activation that was positively correlated with task difficulty. Finally, (iii) a dorsal-ventral and anterior-posterior gradient of functional and structural connectivity was found across the AG (e.g. mid-AG connected with episodic retrieval). We propose a unifying model in which LPC as a whole might share a common underlying neurocomputation (multimodal buffering) with variations in the emergent cognitive functions across subregions arising from differences in the underlying connectivity.
Topics: Semantics; Brain Mapping; Diffusion Tensor Imaging; Parietal Lobe; Memory, Episodic; Magnetic Resonance Imaging
PubMed: 35196706
DOI: 10.1093/cercor/bhac044 -
Neuron Nov 2007Speech analysis is a prototypical categorical mechanism that has been examined behaviorally in work going back to Haskins Laboratory studies in the 1950s: such work... (Review)
Review
Speech analysis is a prototypical categorical mechanism that has been examined behaviorally in work going back to Haskins Laboratory studies in the 1950s: such work examined the perception of continua between phonemes and demonstrated sharp discontinuities consistent with categorical perception. In this issue of Neuron, Raizada and Poldrack examine analysis mechanisms for such processing by measurement of the fMRI BOLD response in the boundary region between different phonemes and argue for a specific amplification mechanism for this type of categorical perception.
Topics: Action Potentials; Brain Mapping; Cerebral Cortex; Cerebrovascular Circulation; Evoked Potentials; Humans; Language; Magnetic Resonance Imaging; Parietal Lobe; Speech Perception
PubMed: 18031677
DOI: 10.1016/j.neuron.2007.11.004 -
The Neuroscientist : a Review Journal... Feb 2013There is considerable interest in the structural and functional properties of the angular gyrus (AG). Located in the posterior part of the inferior parietal lobule, the... (Review)
Review
There is considerable interest in the structural and functional properties of the angular gyrus (AG). Located in the posterior part of the inferior parietal lobule, the AG has been shown in numerous meta-analysis reviews to be consistently activated in a variety of tasks. This review discusses the involvement of the AG in semantic processing, word reading and comprehension, number processing, default mode network, memory retrieval, attention and spatial cognition, reasoning, and social cognition. This large functional neuroimaging literature depicts a major role for the AG in processing concepts rather than percepts when interfacing perception-to-recognition-to-action. More specifically, the AG emerges as a cross-modal hub where converging multisensory information is combined and integrated to comprehend and give sense to events, manipulate mental representations, solve familiar problems, and reorient attention to relevant information. In addition, this review discusses recent findings that point to the existence of multiple subdivisions in the AG. This spatial parcellation can serve as a framework for reporting AG activations with greater definition. This review also acknowledges that the role of the AG cannot comprehensibly be identified in isolation but needs to be understood in parallel with the influence from other regions. Several interesting questions that warrant further investigations are finally emphasized.
Topics: Brain Mapping; Cognition; Diagnostic Imaging; Humans; Image Processing, Computer-Assisted; Meta-Analysis as Topic; Neural Pathways; Parietal Lobe; Reading; Semantics
PubMed: 22547530
DOI: 10.1177/1073858412440596